The invention relates to an adjusting device of a disc brake, in particular of a pneumatically operated disc brake, and to a disc brake containing such an adjusting device.
Adjusting devices on disc brakes are used to compensate for brake linings, which become thinner as a result of wear. The adjusting devices displace the brake linings in the direction of the disc brake in order to set a desired amount of air “play” so that the working stroke necessary for braking remains constant.
Adjusting devices of a generic type are known from the European patent EP 0 531 321 B1 (having a U.S. counterpart U.S. Pat. No. 5,353,896). With regard to the individual details of the functioning of the generic adjusting device, and an example of a disc brake which can be activated by a rotary lever and for which the adjuster of the generic type, but also the adjuster according to the invention, are suitable, reference is made to the entire contents of U.S. Pat. No. 5,353,896, the specification of which is expressed incorporated by reference herein.
The adjusting devices illustrated in EP 0 531 321 B1 have proven to be highly effective. They are arranged in the interior of rotary spindles, which are fitted with pressure elements which act on one of the brake linings. They are suitable for disc brakes of various types, which have in common the fact that they have one or more rotary spindles.
During an adjusting movement when braking, the known adjusting devices transmit, by way of a drive output sleeve, a torque to its associated rotary spindle, which is fitted with the pressure element at its end facing the brake disc. The pressure element acts on the lining carrier plate of a brake lining. The rotational movement of the rotary spindle causes the pressure element to be displaced axially in the direction of the disc brake in order to compensate for a reduction in the thickness of the brake lining material caused by wear. In order to ensure the adjusting function, the adjusting devices generally have a free-wheel, so that the adjuster does not rotate backwards when the brake is released, and an overload coupling which responds when the pressure elements are applied to the brake lining.
The drive output sleeve of the prior art is provided on its outer periphery with at least one radially projecting tooth-like tooth for engaging in at least one corresponding tooth-like groove on the inner periphery of the rotary spindle. Although this arrangement has proven effective, there is needed, in particular, a way to prevent an excessive or insufficient air play adjustment as a result of vibration loading and the like.
Against this background, the invention meets this need by providing an adjusting device further optimized in functionality. The adjusting device reliably prevents, in particular, that an air play is set to too low a value.
According to the invention, an adjusting device of disc brake, in particular of a pneumatically operated disc brake is provided, which adjusting device serves to rotate and, therefore, axially move at least one rotary spindle which is provided with an inner toothing including one or more axially running grooves. The adjusting device has a drive output sleeve with an outer toothing. The outer toothing engages in the inner toothing of the rotary spindle. A single-part or multi-part release spindle, is provided which extends axially through the adjusting device and serves to manually release the adjusting device. The spindle is arranged and/or mounted so as to prevent rotations of the spindle below a limit torque which is greater than the torques caused by vibration loading during operation of the disk brake. The spindle, or a component which is rotationally fixedly connected to the spindle, has an outer toothing, which likewise engages directly in the groove-like inner toothing of the setting spindle.
According to an aspect of the invention, an adjusting device is provided which compensates, without play, for all production tolerances at the interface between the drive output sleeve of the adjusting device and the adjusting rotary spindle (typically a threaded tube) without jamming occurring as the adjusting shaft is rotated and displaced.
In contrast to this, the adjusting properties are positively influenced even in the case of vibration loading, rotation and displacement of the adjuster shaft relative to the threaded tube or rotary spindle shaft, repeated tests on the basis of static application, and combinations of these.
The drive output sleeve and the spindle are, preferably, decoupled from one another, and are, in particular, rotatable relative to one another to a limited extent.
It is particularly preferable for a star-shaped driver to be placed on the spindle, the star-shaped driver being rotationally fixedly connected to the spindle and having the outer toothing which engages in the inner toothing of the rotary spindle.
This can be provided in a simple manner according to a first embodiment of the invention in that the drive output sleeve has a cut-out in its peripheral wall. The star-shaped driver extends radially through the cut-out, with the star-shaped driver having the outer toothing only in the region.
Alternatively, this can also be provided in a simple manner in that the star-shaped driver and the drive output sleeve are arranged so as to be axially offset relative to one another.
The invention also provides a disc brake having the inventive adjusting device.
In summary, the invention offers the advantage of greatly improved functionality with unchanged installation space requirements and approximately unchanged production costs.
Further advantageous embodiments are described and claimed herein.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.